diff --git a/lib/net/imap/sequence_set.rb b/lib/net/imap/sequence_set.rb
index 9bb65f59..dfd82616 100644
--- a/lib/net/imap/sequence_set.rb
+++ b/lib/net/imap/sequence_set.rb
@@ -788,7 +788,11 @@ def disjoint?(other)
       # Related: #min, #minmax, #slice
       def max(count = nil, star: :*)
         if count
-          slice(-[count, size].min..) || remain_frozen_empty
+          if cardinality <= count
+            frozen? ? self : dup
+          else
+            slice(-count..) || remain_frozen_empty
+          end
         elsif (val = max_num)
           val == STAR_INT ? star : val
         end
diff --git a/test/net/imap/test_sequence_set.rb b/test/net/imap/test_sequence_set.rb
index e0c6d6dd..db1f4b6c 100644
--- a/test/net/imap/test_sequence_set.rb
+++ b/test/net/imap/test_sequence_set.rb
@@ -808,6 +808,15 @@ def obj.to_sequence_set; 192_168.001_255 end
     assert_equal SequenceSet["678"],     SequenceSet["345,678"].max(1)
     assert_equal SequenceSet["345,678"], SequenceSet["345,678"].max(222)
     assert_equal SequenceSet.empty,      SequenceSet.new.max(5)
+    # with different cardinality (150) vs size (200)
+    set = SequenceSet["101:200,51:150"]
+    assert_equal SequenceSet["52:200"], set.max(149)
+    assert_equal SequenceSet["51:200"], set.max(150)
+    assert_equal SequenceSet["51:200"], set.max(200)
+    # with different cardinality (2**32) vs count (2**32 - 1)
+    set = SequenceSet[1..]
+    assert_equal SequenceSet["2:*"], set.max(2**32 - 1)
+    assert_equal SequenceSet["1:*"], set.max(2**32)
   end
 
   test "#minmax" do